Telephone system.



No. 69|,664. Patented Jan. 2|, |902. G. RITTER.

TELEPHONE SYSTEM.

(Application led Nav. 2, 1900.) (Ilo Modem' Zwenfm",

clearing-out drop.

matic View illustrating a modification of my UNITED STATES v PATENT OFFICE. v

GEORG RITTER, OF STUTTGART, GERMNY.

TELEPHON E SYSTEM.

SPECIFICATION forming part of Letters Patent No. 691,664, dated January 21, 1902.

Application tiled November 2, 1900. Serial No. 35,271. (No model.)

To 1f/ZZ. whom, it' may concern:

Be itt-known that I, GEORG RITTER, a citizen of the German Empire, residing at Ati-- provements in central-station switchboard apparatus.

The object of the invention is to provide A.means for automatically .switching on the callin g-current to the desired substation-line and for automatically interchanging the central-station telephone and the clearing-out annunciator in the proper sequence.

lVith this object in viewmy invention consists in the features of construction, combinations of parts, and details which will first be described in connection with the accompanying drawings and then particularly.v

pointed out in the claims.

In the drawings, Figure l is a diagrammatic view of so much of a telephone system embodying my invention as is necessary-to, illustrate the same. Fig. 2 is a detail sectional view of one of the improved circuitchanging devices employed by me for switching the calling-current on and oit the-substa' tion-line to be called. Fig. 3 is a similar view of a circuit-closer employed by me for closing the circuit of the magnet which restores the Fig. 4 is a detail diagraminvention. Fig. 5 is a detail sectional view of a circuit-closing device employed in connection with the modification shown in Fig. 4, Fig. G is a detail diagrammatic view illustrating another embodiment of my invention,

t and Fig. 7 is a similar view illustratinga further embodiment of said invention. y

Referring to Fig. l of the drawings, S and S2 are plugs, the former being the answering- The latter plug Szdiffers from the plug S in that it has a conductive portion s in addition to the usual two terminals, which conductive portion is arranged to make au electrical contact with any socket or jack-ring h into which it may be inserted.

At W is shown a special form of circuitchanger for connecting the source of callingcurrent with the line and for cutting oi the said source after a predetermined interval. This circuit-changercomprises two switches, which are identical in construction. Each consists of an outer tube w, Fig. 2, closed at each end, within which is located an inner tube w, closed 'at the lower end only and provided with a hole or series of holes to2 near its middle, the'inner tube being held in place and separated from the outer tube by cement, (indicated at 103,) which extends upward to the lower edge of the said holes cu2. The

tubes are of insulating material, preferably glass, and into the inner tube is placed some mercury w4. Into each end of the outer tube w and projecting Vinto the interior of the inner tube w are two wires, which are connected with the circuit in a manner hereinafter described. These wires are indicated at s' S2, Fig. 2, and are arranged to have their terminals closed by the mercury fw4 when the latter is at the bottom of the inner tube tu', as it is shown in Fig. 2( The wire s2 is provided with a branch terminal s3, which projects between the inner and outer tubes and reaches nearly to the holes w?. A wire r also extends through the exterior tube w and terminates near the holes cu2.

In the circuit-changer W a pair of switch Vdevices such as above described is employed,

each being mounted on trunnionsand both being connected so as to swing simultaneously on said trunnions by means of a frame ws, held yieldinglyin its raised position by means of a spring 10G. The terminals s! s2 of each switch device are connected to the respective terminals of the plugs S S2 bythe wires n n 0 o', which form the connector-conductors, while the terminals r of said switch devices are connected to the terminals of a local circuit R, containing a sourceof call- K telephone and the clearing-ont annunciator in their connections with the talking-circuit,

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said central -station telephone being indiat E. The said main circuit-changer V has two switch-arms o fu', the former being arranged to engage eitherI the contact T or the contact E, while the latter is arranged to engage either the contact T2 or the contact E2. The contacts T T2 form the terminals of the operators telephone set, While the contacts E E2 form the terminals of the main coil E3 of the clearing-out drop E. The two switcharms yv fu are connected to the connector-conductors by the branch conductors n2 02, the latter of which includes a circuit-breaker N, held open by lthe answering-plug S and so arranged as to be closed automatically when the answering-plugis removed from its holder for insertion in the jack-ring of a substation which has called the central office. The switch-arm v is provided with an armature c2, arranged to be attracted by an electromagnet M', whose coil is included in a local circuit terminating at the jack-rings h and at the conductive portion s of the connecting-plug S2, the said circuit being energized by the battery P and composed of conductors w Q0 562 m3 x". The two switch-arms U n' are connected so as to move together-as, for example, by the frame B, which carries a tongue B, pivotally connected at l) to the frame B and arranged to come into contact with the frame 205, whereby the latter is moved by the movement ot' the main circuitchanger V. The said tongue B is provided with a nose b', having an inclined surface arranged to engage an abutment A, fixed against movement in one direction and arranged to swing iu the opposite direction. When the main circuit-changer V is pulled downward by its armature,the frame B moves with it, and the tongue B', which is at that time in contact with the frame w, pushes the latter down against the action of its spring w6 until the inclined surface of the nose b engages the abutment A, whereupon the tongue B is forced to move laterally, swinging upon its pivotal connection b. In this way the tongue B is forced out of engagement with the frame 'w and the latter is released, being therefore again moved to its normal position by its spring wG. The main circuit-changer V is also provided with a spring r3, by means of which itis returned to its normal position when the magnet M is demagnetized.

To the frame B of the main circuit-changer Vis connected a delay-action circuit-closer C, which in this instance comprises a switch device similar to one of those employed in the circuit-changer XV, with the exception, however, that it is provided only with two terminal wires p and e4, which terminate near each other and near the holes in the inner tube, in the space around the said inner tube, as will be understood from Fig. 3. The wiresp and e4, respectively, are the terminals of a branch circuit from the local circuit which is energized by the battery P, the said branch circuit including the restoring-coils E4 of the clearing-out drop.

The operation of the mechanism thus far described is as follows: Vhen the operator receives a call and lifts the answering-plug S for the purpose of' inserting it into the proper jack, the branch circuit to the main circuitchanger V is closed at the circuit-breaker N, so that when the said answering-plug S has been inserted into its jack the central-station telephone T is in circuit with the substationline from which the call is received over the contacts T T2, switch-arms o fu', conductors n2 o2 n o', and the terminals of the answering-plugs. So soon as the operator has ascertained the number of the substation to be called and inserted the connecting-plug S2 in the proper jack, the local circuit from the battery P is closed by the conductive portion s of the plug S2 coming into contact with the jack-ring 7i, and the magnet M is energized, thereby attracting its armature o2 and operating the main circuit-changer V to interchange the clearing-out drop E with the central-station telephone T in its connections to the talking-circuit. The said clearing-out drop will then have its main coil E3 connected to the talking-circuit over the contactpoints E E2, switch-arms o o, branch conductorsn2o2, to the connector-conductors n o. At the same time by the movement of the main circuit-changer V downward the frame w5 of the circuit-breaker W is moved downward and then released,whereupon it is drawn upward to its normal position by its spring w. Upon the downward movement of the said circuit-breaker its switch devices are tipped so that the mercury 104 in the inner tubes w of said switch devices is permitted to run out into the spaces between the inner and outer tubes, said mercury remaining at the ends of said outer tubes. By this actionlthe connection between the two parts n and n o and o of each connector-conductor is broken. Upon the upward movement of the circuit-changer WV the mercury in the switch devices flows down in the spaces around the inner tubes until stopped by the cement fillings w3, and thereby closes the circuits through the terminals s3 and r, thus connecting the local circuit R, containing the source R of callingcurrent, with the line to be called through the parts n and 0 of the connector-conductors and through the terminals of the plug S2. The mercury gradually flows through Ithe holes 102 in the inner tubes of the switch devices, thus cutting off the source of callingcurrent from the line connected with the plug S2, and finally returns to the bottoms of" the inner tubes w', again closing the talkingcircuit across the connector-conductors. In this way the calling-current is automatically sent out over the line to he called and then cut off after a predetermined time, which time depends upon the size and number of the holes '102 in the inner tubes w of the switch devices.

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When the frame B ofthe main circuit-changer is moved, it also tips the delay-action circuit closer and breaker C, whereby the mercury 'within its inner tube flows out of the open 'end of the inner tube and rests at the corresponding end of the outer tube. So soon as 'the magnet M is demagnetized, the spring c3 lifts the main circuit-changer V and with it the frame B, thereby restoring the circuitand energizing the iestoimgmagnet E,

whereby the shutter of the clearing-out annunciatoris restored to its normal position. When the mercury has passed through the holes in the inner tube of the switch device to the bottom of said inner tube, the branch circuit is again broken. The lines are now ready for conversation, and when the same is completed and the subscribers or either of them have rung o the clearing-out drop is operated by the energizing of its coils E3 in the usual manner, the shutter remaining down until the next use of the plug in making another connection, whereupon the shutter is restored by the circuit-closing device C, as previously described.

It will be noted that by this invention the operator has only to insert the answeringplug in the socket of the calling-line, listen at the central-station phone for the message of the calling subscriber, and then insert the connecting-plug in the socket of the line to be called, all other steps necessary in making a connection being performed automatically.

In Fig. 4 I have shown a modified embodiment of my invention, wherein the circuitchanger which throws the callin g-current onto and o the line to be called is changed so. that the mercurial switch devices are not included in the talking-circuit. In this construction the tongue B3, pivoted to the frame B2 of the main circuit-breaker, is released from contact with the frame of the circuitbreaker W by means of an electromagnet M2, which cooperates with its armature m', secured to the tongue B3. The coils of the magnet M2 are included lin al local circuit which includes the source of calling-current R2, a simple switch w", and a delay-action circuit closerand breaker O'. The latteris somewhat similar to one of the switch devices employed in the circuit-changer, hereinabove described, the difference being that it is not.provided with terminals equivalent to those indicated at s3 and r, Fig. 2. The construction of the said delay-action circuit closer and breaker C will be understood from Fig. 5. It is mounted in trunnions and is provided with an end A', arrangedl to be engaged by a nose hzof the main circuit-changer, and is held in its normal position bya spring c2. The circuit-changer W comprises two Vits normal position by a spring w11.

switch-arms w8 109,#each pivoted at one end, the arm w8 being arranged to engage either the contact-point n3 or the contact-point r3, while the switch-arm w is arranged to engage either the contact-point 03'or the contact-point r4. The said contact-points n3 o3 are connected to the wires fn.' o', respectively, of the connector-cond uctors,while the pivotal points of the switch-arms wi wg are connect- I ed, respectively, to the wires n o of the connector-conductors. The contact-points r3 r4 are two terminals of the local circuit which contains the-source R2 of the calling-current. The two switch-arms w8 wf and the switch w? are connected to the frame w10, which is acted on by the tongue B3, said frame being held in The operation of this apparatus is as follows: When the main circuit-breaker Vis drawn down by the action of its magnet M', the frame w10 is also forced'down by the tongue B8 against the action of the spring w11, thereby moving the three switch-arms co7 1087.09, the latter two, (w8 wi) leaving the contact-points n3 03, re-

spectively, and engaging the contact-points r3 r4, respectively, whilethev switch-arm 107 engages the contact-point r5. In this way the connector-conductors n n o o are opened and the source of calling-current R2 connected to the terminals of the connecting-plug- Szover the wires fn o. At the same time the` delayaction circuit closer and breaker C is tipped by the nose b2 'on the tongue B3 and then released, whereby the said circuit closer and breaker C is allowed to return to its normal position. l/Vhen it is first-tipped, the mercury runs out of the inner tube, and thus breaks the local circuit of the battery Il.2 at the terminals fm2 r', Fig. 5. By thetime the circuit closer and breaker again returns to itsv normal position the local circuit is closed at the switch-arm wl, and hence when the mercury has returned through the holes in the inner tube it closes the local circuit through the terminals m2 fr', and thus completes the IIO local circuit. Thereupon the magnet M2 is energized and attracts its armature m', thus drawing the tongue B3 to one side and releasingltheV frame w10, which is then drawn up to its normal position'by the spring/w11, thus..

circuit-changer,'the 'said switch-armi@3 carrying the armature n4 of the magnet Ms and being arranged to wipe over a contact device e5 during the movement of said switcharm o3 in either direction, the contact .between the said switch-arm v3 and the contactdevic'e 'e5 being merely momentary. The 4local circuit which` contains the source R3 of calling-current stands open at the terminals r6 rl and is arranged to be switched onto the conductors n o, leading to the connecting-plug S2, by the circuit-changer W2, which in this case consists of two switch-arms w12 w13, connected by a frame w14, normally drawn upward bya spring w15 and arranged to be engaged by a tongue B4, pivoted to the frame B5 of the main circuit-charger V. The tongue B4 is provided with an armature m3, whereby it is drawn aside to permit the return of the frame w14 to its normal position, the armature being acted upon for this purpose by a magnet M4, included in a grounded branch from the local circuit, which branch contains a source R4 of direct current. At the substation the telephone hook-lever K, which is connected to one limb of the line, is arranged to wipe over a contact ,7c in moving upward, the said contact 7.a being grounded. With this arrangement the source RS may be an alternator, if so desired. In this construction the insertion of the con meeting-plug S2 causes the magnet M3 to be energized and draw down its armature, thereby moving the main circuit-changer and also wiping the end ot' the switch-arm v3 over the contact device e5, thus irst making and then breaking the circuit through the restoring-magnet. This closure of said circuit on the downward movement of the arm v3 is without function, except in case the drop has accidentally been tripped. The downward movement of the main circuitchanger causes the calling-current from the source R3 to be sent out upon the line to be called. As soon as the subscriber at the called station takes the receiver ott its hook K the latter moves upward, temporarily closing the grounded circuit through the magnet M4, and thereby drawing the tongue to one side and releasing the frame w14, which is returned to its normal position by its spring, thereby cutting oi the calling-current and closing the talking-circuit across the connector-conductors.

The construction shown in Fig. 7 differs from that in Fig. 6 in employing a source R5 of calling-current which supplies direct instead of alternating current. Hence this source serves to energize the magnets M5 when the subscriber closes the grounded circuit temporarily by the removal of the substationtelephone. For this reason the batte ry shown at R4 in Fig. 6 is not required in the construction shown in Fig. 7.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a telephone system, the combination with the substation-jacks, a pair of plugs, their connecting-conductors, and a centralstation telephone, of connections between the said telephone and the connecting-conductors, a clearing-out annunciator, circuit-changing means operated by the insertion of the connecting-plug in a jack and arranged when operated to substitute the clearing-out annunciator for the central station in the talking-circuit, a source of calling-current, callcirc uit-closin g mechanism for connecting said source with the substation-line to be called, a connecting device between the circuitchanging means and the said call-circuit-closing mechanism, whereby the latter is actuated by the former, releasing mechanism for releasing the said call-circuit-closing mechanism from the control of said connecting device, and means for returning the call-circuitclosing mechanism to its initial position.

2. In a telephone system, the combination, with the substation-jacks, a pair of plugs, their connecting-conductors, and a centralstation telephone, a holder for the answeringplug when not in use, means operated bythe removal of the answering-plug from its holder for connecting the central-station telephone with the calling-line, a clearing-out annunciator, circuit-changing means operated by the insertion of the connecting-plugin a jack for substituting the clearing-out annunciator for the central-station telephone in the talking-circuit, a source of calling-current, callcircuit-closing mechanism for connecting said source with the substation-line to be called, a connecting device between the circuit-changing means and the said call-circuit-closing mechanism whereby the latter is actuated by the former, releasing mechanism for releasing the said call-circuit-closing mechanism from the control of said connecting device, and means for returning the call-eircuit-closing mechanism to its initial position.

3. In a telephone-system, the combination with the substation-jacks connected to the respective substation-lines, jack-sockets for said jacks and a pair of plugs, comprising an answering-plug and a connecting-plug, the latter having a conductive portion to engage the jack-socket when inserted therein, of a pair of delay-action circuit-changers, connecting-conductors from said delay-action circuitchangers to the terminals of the two plugs, a source of calling-current, a local circuit in which said source is inclosed, said circuit having its terminals connected to the delay-action circuit-changers, a central-station telephone, an electric self-restoring clearing-out drop, a pair of branch conductors from the connectorconductors of the answering-plug, a main circuit-changer for interchangeably connecting the central-station telephone and the main coil of the clearing-out drop to the branch conductors of the answering-plug, a holder to receive the answering-plug when not in use, a switch in one of the branch conductors, said switch being arranged to be held open when the answering-plug is in the holder, an electromagnet for operating the main circuitchanger, a local circuit-changer-circuit in which are included the coils of the said electromagnet, the sockets of the jacks and conductive portion of the connecting-plug, means for energizing said circuit, a branch from said local circuit-changer-circuit, in parallel with IOO IIO

the coils of the electi'oinagnet, and including ing-out annunciator in the talking-circuit, a source of calling-current, means operated by the insertion of the connecting-plug in a jack for operating the main circuit-changer and switching the source of calling-current onto the line with which the terminals of the connecting-plng are connected, and rneansactuated by the called-subscriber for cutting oft the source of calling-current from said line. lIn testimony Whereot` I afx my signature 1n presence of two Witnesses. I

GEORG RITTER.

Witnesses: v

AUGUST DRAUTZ, JULIUS HAEUSSERMAML` 

